From: Junyan He <junyan.he@intel.com>

Add a pair of configure options --{enable,disable}-libpmem to control
whether QEMU is compiled with PMDK libpmem [1].

QEMU may write to the host persistent memory (e.g. in vNVDIMM label
emulation and live migration), so it must take the proper operations
to ensure the persistence of its own writes. Depending on the CPU
models and available instructions, the optimal operation can vary [2].
PMDK libpmem have already implemented those operations on multiple CPU
models (x86 and ARM) and the logic to select the optimal ones, so QEMU
can just use libpmem rather than re-implement them.

[1] PMDK (formerly known as NMVL), https://github.com/pmem/pmdk/
[2] https://github.com/pmem/pmdk/blob/38bfa652721a37fd94c0130ce0e3f5d8baa3ed40/src/libpmem/pmem.c#L33

Signed-off-by: Junyan He <junyan.he@intel.com>
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
---
 configure | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/configure b/configure
index 2a7796e..1c9288b 100755
--- a/configure
+++ b/configure
@@ -475,6 +475,7 @@ vxhs=""
 libxml2=""
 docker="no"
 debug_mutex="no"
+libpmem=""
 
 # cross compilers defaults, can be overridden with --cross-cc-ARCH
 cross_cc_aarch64="aarch64-linux-gnu-gcc"
@@ -1435,6 +1436,10 @@ for opt do
   ;;
   --disable-debug-mutex) debug_mutex=no
   ;;
+  --enable-libpmem) libpmem=yes
+  ;;
+  --disable-libpmem) libpmem=no
+  ;;
   *)
       echo "ERROR: unknown option $opt"
       echo "Try '$0 --help' for more information"
@@ -1710,6 +1715,7 @@ disabled with --disable-FEATURE, default is enabled if available:
   vhost-user      vhost-user support
   capstone        capstone disassembler support
   debug-mutex     mutex debugging support
+  libpmem         libpmem support
 
 NOTE: The object files are built at the place where configure is launched
 EOF
@@ -5546,6 +5552,24 @@ if has "docker"; then
 fi
 
 ##########################################
+# check for libpmem
+
+if test "$libpmem" != "no"; then
+	if $pkg_config --exists "libpmem"; then
+		libpmem="yes"
+		libpmem_libs=$($pkg_config --libs libpmem)
+		libpmem_cflags=$($pkg_config --cflags libpmem)
+		libs_softmmu="$libs_softmmu $libpmem_libs"
+		QEMU_CFLAGS="$QEMU_CFLAGS $libpmem_cflags"
+	else
+		if test "$libpmem" = "yes" ; then
+			feature_not_found "libpmem" "Install nvml or pmdk"
+		fi
+		libpmem="no"
+	fi
+fi
+
+##########################################
 # End of CC checks
 # After here, no more $cc or $ld runs
 
@@ -6010,6 +6034,7 @@ echo "replication support $replication"
 echo "VxHS block device $vxhs"
 echo "capstone          $capstone"
 echo "docker            $docker"
+echo "libpmem support   $libpmem"
 
 if test "$sdl_too_old" = "yes"; then
 echo "-> Your SDL version is too old - please upgrade to have SDL support"
@@ -6763,6 +6788,10 @@ if test "$vxhs" = "yes" ; then
   echo "VXHS_LIBS=$vxhs_libs" >> $config_host_mak
 fi
 
+if test "$libpmem" = "yes" ; then
+  echo "CONFIG_LIBPMEM=y" >> $config_host_mak
+fi
+
 if test "$tcg_interpreter" = "yes"; then
   QEMU_INCLUDES="-iquote \$(SRC_PATH)/tcg/tci $QEMU_INCLUDES"
 elif test "$ARCH" = "sparc64" ; then
-- 
2.7.4

On Tue, 10 Jul 2018 14:06:26 +0800
junyan.he@gmx.com wrote:

> From: Junyan He <junyan.he@intel.com>
> 
> Add a pair of configure options --{enable,disable}-libpmem to control
> whether QEMU is compiled with PMDK libpmem [1].
> 
> QEMU may write to the host persistent memory (e.g. in vNVDIMM label
> emulation and live migration), so it must take the proper operations
> to ensure the persistence of its own writes. Depending on the CPU
> models and available instructions, the optimal operation can vary [2].
> PMDK libpmem have already implemented those operations on multiple CPU
> models (x86 and ARM) and the logic to select the optimal ones, so QEMU
> can just use libpmem rather than re-implement them.
> 
> [1] PMDK (formerly known as NMVL), https://github.com/pmem/pmdk/
pls use document names in addition to links that could be found using search engine

> [2] https://github.com/pmem/pmdk/blob/38bfa652721a37fd94c0130ce0e3f5d8baa3ed40/src/libpmem/pmem.c#L33
it probably would be better to point out a specific specs/chapters
that describe difference. since the link can disappear and line change
so reader of commit message won't have any clue what [2] meant.

> 
> Signed-off-by: Junyan He <junyan.he@intel.com>
> Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> Reviewed-by: Igor Mammedov <imammedo@redhat.com>

patch probably should be reordered and placed before 
[PATCH 3/7 V8] hostmem-file: add the 'pmem' option

> ---
>  configure | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/configure b/configure
> index 2a7796e..1c9288b 100755
> --- a/configure
> +++ b/configure
> @@ -475,6 +475,7 @@ vxhs=""
>  libxml2=""
>  docker="no"
>  debug_mutex="no"
> +libpmem=""
>  
>  # cross compilers defaults, can be overridden with --cross-cc-ARCH
>  cross_cc_aarch64="aarch64-linux-gnu-gcc"
> @@ -1435,6 +1436,10 @@ for opt do
>    ;;
>    --disable-debug-mutex) debug_mutex=no
>    ;;
> +  --enable-libpmem) libpmem=yes
> +  ;;
> +  --disable-libpmem) libpmem=no
> +  ;;
>    *)
>        echo "ERROR: unknown option $opt"
>        echo "Try '$0 --help' for more information"
> @@ -1710,6 +1715,7 @@ disabled with --disable-FEATURE, default is enabled if available:
>    vhost-user      vhost-user support
>    capstone        capstone disassembler support
>    debug-mutex     mutex debugging support
> +  libpmem         libpmem support
>  
>  NOTE: The object files are built at the place where configure is launched
>  EOF
> @@ -5546,6 +5552,24 @@ if has "docker"; then
>  fi
>  
>  ##########################################
> +# check for libpmem
> +
> +if test "$libpmem" != "no"; then
> +	if $pkg_config --exists "libpmem"; then
> +		libpmem="yes"
> +		libpmem_libs=$($pkg_config --libs libpmem)
> +		libpmem_cflags=$($pkg_config --cflags libpmem)
> +		libs_softmmu="$libs_softmmu $libpmem_libs"
> +		QEMU_CFLAGS="$QEMU_CFLAGS $libpmem_cflags"
> +	else
> +		if test "$libpmem" = "yes" ; then
> +			feature_not_found "libpmem" "Install nvml or pmdk"
> +		fi
> +		libpmem="no"
> +	fi
> +fi
> +
> +##########################################
>  # End of CC checks
>  # After here, no more $cc or $ld runs
>  
> @@ -6010,6 +6034,7 @@ echo "replication support $replication"
>  echo "VxHS block device $vxhs"
>  echo "capstone          $capstone"
>  echo "docker            $docker"
> +echo "libpmem support   $libpmem"
>  
>  if test "$sdl_too_old" = "yes"; then
>  echo "-> Your SDL version is too old - please upgrade to have SDL support"
> @@ -6763,6 +6788,10 @@ if test "$vxhs" = "yes" ; then
>    echo "VXHS_LIBS=$vxhs_libs" >> $config_host_mak
>  fi
>  
> +if test "$libpmem" = "yes" ; then
> +  echo "CONFIG_LIBPMEM=y" >> $config_host_mak
> +fi
> +
>  if test "$tcg_interpreter" = "yes"; then
>    QEMU_INCLUDES="-iquote \$(SRC_PATH)/tcg/tci $QEMU_INCLUDES"
>  elif test "$ARCH" = "sparc64" ; then